Joint injuries may commonly result in the complete or partial detachment of ligaments, tendons and soft tissues from bone. Tissue detachment may occur in many ways, e.g., as the result of an accident such as a fall, overexertion during a work related activity, during the course of an athletic event, or in any one of many other situations and/or activities. These types of injuries are generally the result of excess stress or extraordinary forces being placed upon the tissues.
In the case of a partial detachment, commonly referred to under the general term “sprain,” the injury frequently heals without medical intervention, the patient rests, and care is taken not to expose the injury to undue strenuous activities during the healing process. If, however, the ligament or tendon is completely detached from its attachment site on an associated bone or bones, or if it is severed as the result of a traumatic injury, surgical intervention may be necessary to restore full function to the injured joint. A number of conventional surgical procedures exist for re-attaching such tendons and ligaments to bone.
One such procedure involves the re-attachment of the detached tissue using “traditional” attachment devices such as staples, sutures, and bone screws. Such traditional attachment devices have also been used to attach tendon or ligament grafts (often formed from autologous tissue harvested from elsewhere in the body) to the desired bone or bones. In one procedure, a damaged anterior cruciate ligament (“ACL”) is replaced by a ligament graft in a human knee.
Two popular approaches to ACL reconstruction include a transtibial approach and an anteromedial approach. In the transtibial approach, a surgeon will first drill a tunnel through a tibia and insert a guide pin through the tunnel and through intra-articular space between a femur and the tibia to locate and drill an aligned femoral tunnel. Once the guide pin is placed, a reamer overdrills the guide pin and passes into the femur to create a final diameter of the femoral tunnel in which a ligament graft can be positioned and secured. The ligament graft is ultimately secured to the tibia using the tibial tunnel to complete the repair. Drilling the tibia can damage and/or weaken the tibia. Additionally, it can be difficult to determine the proper angle to drill through the tibia to achieve the desired anatomic femoral tunnel position, which can increase time of the surgical procedure and/or can dictate the placement of the femoral tunnel away from the desired location.
In the anteromedial approach, a surgeon inserts the guide pin directly into the femur through the intra-articular space, which renders initial drilling of the tibia unnecessary. However, due to the “shallow” angle of approach directly into the femur, the trajectory brings the guide pin much closer to articular cartilage in the intra-articular space than in the transtibial approach. Since generally a reamer has a larger diameter than the guide pin, it can be challenging to place the reamer over the guide pin without scraping or damaging the articular cartilage because of inadequate clearance in the anteromedial approach.
Accordingly, there remains a need for improved methods and devices for surgical guide pin placement.